Listening and ringing key for telephone-switchboards



(No Model.)

. W. M. GOODRIDGE. LISTENING AND RINGING KEY EOE TELEPHONE SWITGHBOARDS.

No. 493,704. Patented Mar. 21,1893.

UNITED STATES PATENT OFFICE.

WILLIAM M. GOODRIDGE, OF HIGHLAND PARK, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS.

LISTENING AND RINGING KEY FOR TELEPHONE-SWITCHBOARDS.

SPECIFICATION forming part of Letters Patent No. 493,704, dated March 21, 1893. Application filed July 19, 1890- Serial No. 359,247. (No model.)

To all whom it may concern.-

Be it known thatI, WILLIAM M. GOODRIDGE, a citizen of the United States, residing at Highland Park, in the county of Lake and State of Illinois, have invented a certain new and useful Improvement in Listening and Ringing Keys for Telephone-Switchboards, (Case No. 15,) of which the following is a full, clear, c011- cise, and exact description, reference being to had to the accompanying drawings, forming a part of this specification.

My invention relates to combination ringing and listening keys for use on multiple switch boards at the central station of a teler 5 phone exchange system.

The object of my invention is to provide means whereby the operator may readily take a subscribers order, complete his connection and ring up the called subscriber.

I have shown my inventionas used in connection with a system of grounded telephone lines. One of my ringing and listening keys is provided for each pair of connecting plugs and cords.

The principal features of my invention consist in a flat metallic spring lever secured at one end to an insulating block and adapted at its free end to be moved into and out of contact with a connection to the operators 3o telephone by means of a cam and lever moving on a pivot provided therefor on the insulating block together with two other metallic springs, each of which forms the terminal of a plug and cord and which are secured to the insulating base in such position that their free ends bear upon contacts provided therefor upon the heel of the main spring lever. Above each of these two terminal springs are placed push buttons, whereby the respective 4o springs may be forced away from contact with the heel of the main spring lever, which is adapted to connect with the operators telephone, and into contact with a strip connected to a common generator.

My invention will be readily understood by reference to the accompanying drawings, in which- Figure 1 is a sectional elevation of one of my combination ringing and listening keys 5o embodying my invention, the section being taken upon line m--w of Fig. 2. Fig. 2 is a plan of "the same from below,in connection with a pair of plugs, operators set and generator.

In Fig. 1 the combination key is shown attached to a portion of the switch board.

As shown one end of the main metallic spring lever a is secured to the insulating block b. The other end normally rests upon the contact 0. The contact 0 is connected directly with the operators set d through the strip 6. The cam and lever f swings upon the pivot g provided upon the insulating block b and is held against lateral movement by the guiding slot in the block b as shown. The cam and leverf being in the position shown by full lines the operators telephone set (I is out out, while, it in the position shown by dot ted lines the operators set (1 would be in circuit. There is enough strength in the spring a to hold the cam f against a slight movement.

The two fiat metallic springs h h form the terminals of the pair of connecting plugs 11 2', are secu red to the insulating block b as shown and rest normally upon the contacts j j provided upon the heel of the main spring lever a. Thus if the two plugs are inserted in the jacks of two lines the circuit is completed through the'said heel or practically through the main spring lever a. Hence the operator may listen in by merely cutting in her tele- 8o phone at c. i

A push key 70 is provided over each of the terminal springs h by means of which the said springs h maybe separated from contact with the heel of "the main spring lever and pressed down against the generator strip Z. Thus current fromthe generator m may be sent over either or both of the lines with which the plugs Zare connected'without danger of giving the operator an unpleasant ring in her telephone.

In order that dust may not accumulate between the points of the various contacts I provide as shown sharp points and edges for the lower contact places. The dust is continually shaken from these and hence the contacts are kept clean.

For convenience I usually place several sets of ringing and listening keys upon the same strip of insulating material. In such arrange- IOO ment the telephone and generator strips e and Z are common,

The operation of my combination ringing and listening key is as follows: When an operator sees an annunciator drop fall she immediately inserts one of the pair of plugs 2' into the answering jack of that line, thus bringing her telephone d into connection with the subscriber. The circuit being through the subscribers line to the connecting plug, thence by the cord to the metallic spring h forming the terminal thereof, thence through the main spring lever a to the contact 0 connecting with the operators set (1, and thence to ground. This connection being made the operator takes the number of the line wanted and immediately places the other plug of the pair in the spring jack terminal of that line. She

' may then cut out her'telephone' by throwing back the spring'lever f and proceed to push down the button 70 over the spring h which forms the terminal of'the line called for, thus sending generator current over the line to ring the called subscribers bell. This being done she releases the push button 70 when her set is entirely out out from the connected "lines and she is free to make other connec- 1 tions.

If,-however, the operator should wish to listen in'for any reason she maydo so by merely throwing the cam lever f forward. In

doing so,the' main spring lever a is allowed to come against its contact, thuscutting in her telephone set between the talking lines. Having thus described my invention, I claim as new and desire to secure by Letters Patentv 1. Ina ringing and listening key the combination of the insulating block, the main metallic spring lever, the cam and lever piv- "otedon the said insulating block and adapted 'to'force the said spring lever out of contact "with a connection to the operators telephone set, the two terminal metal springs, the contacts therefor provided on the heel of the said main spring lever, the generator strip;

' the push buttons, said terminal springs adapt ed to be forced into contact with said generator strip and out of contact with the heel of the said main spring lever by the said push buttons, substantially as shown and described.

I 2. The combination of the insulating block with the main metallic spring lever secured "thereto and provided at the fixed end with two contacts, the cam and lever, the pivot thereof secured to the said insulating block,

' the contact forming a connection with the and in the opposite position to allow said spring to rest on the said contacts, the metallic springs forming the terminals of apair of plugs and cords and normally resting on the said contacts provided on the fixed end of the said main spring lever, the push buttons one over each terminal spring, the common generator strip, said terminal springs being adapted to be carried away from their contacts on the main spring lever and into contact with the said generator strip, substantially as shown and described.

3. The combination of the insulating base b with the'main metallic spring lever on, the contact 0 on which said spring lever a normally rests, the metallic terminal springs h secured to said'base b, the contacts upon the end,said main spring lever a upon which the said terminal springs normally rest,"the generator stripl, the-push buttons'k, one for each terminal spring by means'of which the said springs are pressed away from theirnormal contacts-and into "contact with the said generator strip, substantially as shownand described.

4. In a switch board connecting and listening apparatus, a conductinginterconnecting section for connecting any two'lines comprisinga pair of plug connectors unitedby fiexible conductors, and intermediate contact springs; a set of operators telephones'normally in electricalconnection'withthe said interconnecting sectionwhereby it is brought into circuit with any line intermediatelyupon the connection of either plug with said line; and means as indicated, for disconnecting the said telephones from thesaid interconnecting section when desired without electrically opening said inter-connecting section.

5. A telephone switch board listening and ringing appliance, comprising a normal but separable electrical connection between the twoplug connectors of a'pair constituting an interconnecting link 'for any two lines and the operators telephones; means substantially as indicated for connecting eith'er'of saidplu g connectors independently to a call generator for sending an outgoing signal;-and a'cam lever circuit controller acting simultaneously uponthe said separable connections of the said pair of plugs to disconnect them when in use from the said operators telephones.

In witness whereof I hereunto subscribe my name'this 7th dayof January,'A. D. 1890.

WILLIAM GOOD'RID GE.

Witnesses:

ELLA EDLER, CHAS. G. HAWLEY. 

